When clicking fetch source data on a post with a source such as pixiv, you are given this option: (Create new artist). This creates an artist entry automatically, but I've seen two issues with this:
1. The artist name gets automatically set to the pixiv stacc name. Most howto pages on creating artist entries advise against using the stacc username and using the artist's real name instead (if known obviously). Also, the pixiv nickname gets added to the Other Names field even if it is the exact same spelling as the stacc name.
2. There are some issues with adding URLs. The stacc link no longer gets added automatically to the entry even though the stacc name is used for the tag name. Also, duplicate URLs that have different capitalization get added even if they are the same link.
Both of the issues are shown here where having the stacc name and URL twice just clutters the entry. Another example of this issue is artist #180110 which was named as the stacc name, despite the artist going by Regalpad on most other sites. Additionally, the artist entries here that list the artist as "user_xxxxxxxx" instead of their name.
Edit: When looking at artist entries I noticed that some users accidentally enter the additional names with commas instead of spaces (which adds the comma to the artist name) here. Also, different example is artist #179810 from here where the name that originally included spaces gets separated unless each space is manually changed to an underscore.
Updated